There isn’t really agreement regarding where students should be after an intermediate, advanced course etc.

Some work was done on the topic by Van Ek and the Council of Europe (I think in the 1970’s). You could put these names into a search engine and see what comes up. The Council of Europe is also currently doing some work on levels.

You could also look at the UCLES (University of Cambridge Local Examinations Syndicate) website and see what they say about levels. You could also look at Toefl and Toeic websites.

I’m sorry I can’t come up with more ideas but there isn’t a lot written on the topic.